Technical Abstract:
Mycotoxins are fungal metabolites that can contaminate foods and feeds and exhibit toxic effects in higher organisms, thereby causing a serious food safety problem and affecting the competitiveness of U.S. agriculture in both domestic and world export markets. This article highlights the research that has been accomplished by ARS laboratories in control of preharvest toxin contamination by using biocontrol, host plant resistance enhancement, and integrated management systems. Emphasis will be placed upon the most economically relevant mycotoxins, namely aflatoxins, trichothecenes and fumonisins. Significant inroads have been made in establishing various control strategies such as development of atoxigenic biocontrol fungi that can out compete their closely related, toxigenic cousins in field environments, thus reducing levels of mycotoxins in the crops. Potential biochemical and genetic resistance markers have been identified in crops, particularly in corn, which are being utilized as selectable markers in breeding for resistance to aflatoxin contamination. Prototypes of genetically engineered crops have been generated which resist infection by mycotoxigenic fungi. Gene clusters housing the genes governing the formation of trichothecenes, fumonisins, and aflatoxins have been elucidated and are being targeted in strategies to interrupt the biosynthesis of these mycotoxins. Ultimately, a combination of strategies using biocompetitive fungi, enhancement of host plant resistance, and interruption of mycotoxin biosynthetic processes may prove to be effective in prevention of mycotoxin contamination in the field. This research potentially could save agricultural industries hundreds of millions of dollars during years of serious mycotoxin outbreaks.

Technical Abstract:
Mycotoxins are fungal metabolites that can contaminate foods and feeds and exhibit toxic effects in higher organisms, thereby causing a serious food safety problem and affecting the competitiveness of U.S. agriculture in both domestic and world export markets. This article highlights the research that has been accomplished by ARS laboratories in control of preharvest toxin contamination by using biocontrol, host plant resistance enhancement, and integrated management systems. Emphasis will be placed upon the most economically relevant mycotoxins, namely aflatoxins, trichothecenes and fumonisins. Significant inroads have been made in establishing various control strategies such as development of atoxigenic biocontrol fungi that can out compete their closely related, toxigenic cousins in field environments, thus reducing levels of mycotoxins in the crops. Potential biochemical and genetic resistance markers have been identified in crops, particularly in corn, which are being utilized as selectable markers in breeding for resistance to aflatoxin contamination. Prototypes of genetically engineered crops have been generated which resist infection by mycotoxigenic fungi. Gene clusters housing the genes governing the formation of trichothecenes, fumonisins, and aflatoxins have been elucidated and are being targeted in strategies to interrupt the biosynthesis of these mycotoxins. Ultimately, a combination of strategies using biocompetitive fungi, enhancement of host plant resistance, and interruption of mycotoxin biosynthetic processes may prove to be effective in prevention of mycotoxin contamination in the field. This research potentially could save agricultural industries hundreds of millions of dollars during years of serious mycotoxin outbreaks.